Busulfan versus 32P in polycythaemia vera.

In 293 patients with previously untreated polycythaemia vera, two different treatment modalities were randomized: 32P (0.5-1 mCi/10 kg at diagnosis and for each overt relapse) versus busulfan (4-6 mg/day during 4-8 weeks, with re-administration at relapse). Duration of remission was significantly longer after busulfan (median not equal to 4 years) than after 32P (median not equal to 2 years). Moreover, overall survival was slightly but significantly longer in patients treated with busulfan, with a trend towards increased mortality related to vascular complications or secondary cancers in the 32P group.